Light Up (Akari) is a logic puzzle with simple rules and challenging solutions.

The rules are simple.
Light Up is played on a rectangular grid. The grid has both black cells and white cells in it.
The objective is to place light bulbs on the grid so that every white square is lit.
A cell is illuminated by a light bulb if they're in the same row or column, and if there are no black cells between them.
Also, no light bulb may illuminate another light bulb.
Some of the black cells have numbers in them.
A number in a black cell indicates how many light bulbs share an edge with that cell.
Left click a square to place a light bulb. Right click to mark with X.